
ECSS‐E‐ST‐32‐01CRev.1
6March2009
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e. Standard NDI shall provide crack detection to at least 95% confidence
and90%probabilitylevel.
NOTE
Table 10‐1 gives, for various NDI techniques
andpartgeometries,thelargestcracksizesthat
canremainundetectedattheseprobabilityand
confidencelevels.
f. RadiographicNDIstandard flaw sizes(that are only applicableforflaw
orientationintheX‐radiationplane)shallnotapplytoverytightflaws.
NOTE
Forexample,tightflawsare:forgingflaws,heat
treatment induced flaws, welding induced
cracks, fatigue cracks, flaws in compressive
stressfield.
g. For tight flaws referred to in
10.4.2.1f, special NDI requirements shall
applyasdefinedin
10.4.2.2.
10.4.2.2 Special NDI
a. Special NDI shall be used only in special cases where limited life is
demonstrated for standard initial crack sizes and serious problems can
occur as a result of redesign or acceptance of the limited life, and its
applicationissubjecttoapprovalbythe customer.
b. A statistical demonstration of
90% probability of detection with 95%
confidenceshallbeperformedforthespecialNDImethod.
NOTE The demonstration is specific to the relevant
procedure,partandindividualinspector.
c. The demonstration specified in
10.4.2.2b shall be carried out on
specimensrepresentativeoftheactualconfigurationtobeinspected.
d. For NDI processes which are fully automated, the statistical
demonstration of
10.4.2.2b may be replaced by verification by test of
processparametersandtheirtoleranceswhichcanaffectthesensitivity.
NOTE Forexample,automatededdycurrentscanning.
e. Intheverificationbytestspecifiedin
10.4.2.2d,aminimumof5samples
shallbeused,whichcoverthefullrangeofparametersofthecrackstobe
detected by the automated process, in combination with the structural
detailstobeinspected.
10.4.2.3 Crack Screening Proof Test
a. Where proof testing of a flight item is performed as a screening or
inspection technique for cracks, which are larger than the initial cracks
used in the analytical life prediction, in the proof tests performed,
proceduresandstressanalysispredictionsshallensurethatthepredicted
stresslevelanddistributionare
actuallyachieved,andthattheabsenceof
testfailureensuresthatthecracksofthesizestobescreenedoutarenot
presentinanycriticallocationorinanyorientationoftheitem.
b. Where proof testing of a flight item is performed as a screening or
inspection technique
for cracks, which are larger than the initial cracks